128 



(Hiarlcrs. 'I'licsc were IoiiihI wiiiidcrin^ ;il)(iiil the sinlks. An nliiKtst. 

 microscopic cxaiiiiiKirKni ol stalks which had siipiioilcd thousands of 

 aphides was made alter the lice disappcaic(|, without liiidiii^ an cf^'fi;." 

 (I<\)urt('(Mitli Rep. State Knt. 111., pp. '11, L'S.) Noveuiher 17. l/icc 

 (nioslly W'iii<;ed \i\ipai()us females) kept within doors still active. 

 November "JO. ('aiciul search of <2;rasses about- corn lields revealed various 

 |)lanl-lice but no Aphis tiniidis. Not wit hstandini;' lli(> closest search 

 and the dissection of hundreds of jilant-lice of all forms and stages, no 

 (-races of ej^^s were foiuid, and the conclusion was reacheil I hut the 

 species (certainly does not hibei'natc in (he e«;'^' sta,!;e on or about corn. 



iNSI'lCr \!v^' K\ I'KlilMI'A'rS. 



Inseclary experiments were beii;im in (>ctobei', ISSS, with a \iew 

 to ascortainini', whether an oviparous i;-enei'ation could be pioduced in 

 I'illl, or at any time during' the winter, by continuous breedini; accom- 

 panied b\' cli;ini;('S of temperature. This work, placed in charge of 

 Mr. John Marten, was carried on by him from ( )ctober '.) to Mai'idi I'.). 

 These expeiiments wci'e conducted on seven lots ol specimens, which 

 may be numbered accoi'ilin,i;l\'. .Ml these lots were kept in the I nivci- 

 sity greenhouse, to which they were transfei'red ( )clober II. 



In No. I, N'ouni;' corn stocked with A j>lns hkikIis was i^rowii in pots in 

 (he open air, no precautions beini; taken to prevent the escape i)}i the 

 insects. In No. 2 the insects wei'e conlined mider a small bell-ii'lass, 

 over an earthen pot containint;' coi'u, wheat, j^rass, pmslane, ami apple. 

 It was the object of this experiment to ascertain whether the plantdice 

 would leave corn foi' any one of the other plants mi-ntione(|, maturini;' 

 there a bisexual ,i;ener;il ion. No.."! containeil plaid lice midei" a bell 

 f!;lass with only wheat and apple at (irst, younti; corn beini; ;idde(| l.der. 

 Iti No. I, wheat and corn onlv wer(> used, ami in .No. ">, w heal alone. In 

 No. () ail isolated wiii.i;ed female was placed on wheat plants, under a 

 separate bell-<;lass, with a view to follow iiii; the series of i;,eiierat ions 

 (hrou,u,hoilt th(> winter. No. 7 was identical with ('», except that this lot 

 was expos(Ml to cold in the open air, with a view to determining; 

 whether a bisexual i;;eiieratioii ini^lit thus be produced. 



I'lx jH riiiu III I. OjHii-tiir I xjH riiiii III . (tctobcr •>, iSSS. .Vdiilt 

 Aphis imtidis t I'ansferi'ed frt)iii broom-corn, brought in Iroiii the lield 

 about two weeks apt, to vouiii!: corn urowiii^ in pots. .Most ol the lice 

 w.andered ;iwav from the corn and jiersisted in leavini; it, althoUf;l» 

 replaced several times. ( >iily live remained on tli(> plant at the close of 

 the day. ( >ctober 10. Miiilil ailults and ten vduiiii on the corn, the 

 latter doubtless born duriiii.;; the ni^lit . ( )ctober I'J. NOuiii; still appear- 

 iiiii;, but total number of plant lice does not seem to increase, some 

 apparently wanderiiii:, away. ()ctober l.">. .\ddilion;il pl;inl lice traiis- 

 I'erriHl from broom-coiii and ears of corn to the youiii; corn in pots. 



